gdb/amd64fbsd-nat.c

   1 /* Native-dependent code for FreeBSD/amd64.
   2
   3    Copyright (C) 2003-2004, 2007-2012 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "inferior.h"
  22 #include "regcache.h"
  23 #include "target.h"
  24
  25 #include "gdb_assert.h"
  26 #include <signal.h>
  27 #include <stddef.h>
  28 #include <sys/types.h>
  29 #include <sys/ptrace.h>
  30 #include <sys/sysctl.h>
  31 #include <machine/reg.h>
  32
  33 #include "fbsd-nat.h"
  34 #include "amd64-tdep.h"
  35 #include "amd64-nat.h"
  36 #include "amd64bsd-nat.h"
  37 #include "i386-nat.h"
  38 \f
  39
  40 /* Offset in `struct reg' where MEMBER is stored.  */
  41 #define REG_OFFSET(member) offsetof (struct reg, member)
  42
  43 /* At amd64fbsd64_r_reg_offset[REGNUM] you'll find the offset in
  44    `struct reg' location where the GDB register REGNUM is stored.
  45    Unsupported registers are marked with `-1'.  */
  46 static int amd64fbsd64_r_reg_offset[] =
  47 {
  48   REG_OFFSET (r_rax),
  49   REG_OFFSET (r_rbx),
  50   REG_OFFSET (r_rcx),
  51   REG_OFFSET (r_rdx),
  52   REG_OFFSET (r_rsi),
  53   REG_OFFSET (r_rdi),
  54   REG_OFFSET (r_rbp),
  55   REG_OFFSET (r_rsp),
  56   REG_OFFSET (r_r8),
  57   REG_OFFSET (r_r9),
  58   REG_OFFSET (r_r10),
  59   REG_OFFSET (r_r11),
  60   REG_OFFSET (r_r12),
  61   REG_OFFSET (r_r13),
  62   REG_OFFSET (r_r14),
  63   REG_OFFSET (r_r15),
  64   REG_OFFSET (r_rip),
  65   REG_OFFSET (r_rflags),
  66   REG_OFFSET (r_cs),
  67   REG_OFFSET (r_ss),
  68   -1,
  69   -1,
  70   -1,
  71   -1
  72 };
  73 \f
  74
  75 /* Mapping between the general-purpose registers in FreeBSD/amd64
  76    `struct reg' format and GDB's register cache layout for
  77    FreeBSD/i386.
  78
  79    Note that most FreeBSD/amd64 registers are 64-bit, while the
  80    FreeBSD/i386 registers are all 32-bit, but since we're
  81    little-endian we get away with that.  */
  82
  83 /* From <machine/reg.h>.  */
  84 static int amd64fbsd32_r_reg_offset[I386_NUM_GREGS] =
  85 {
  86   14 * 8, 13 * 8,               /* %eax, %ecx */
  87   12 * 8, 11 * 8,               /* %edx, %ebx */
  88   20 * 8, 10 * 8,               /* %esp, %ebp */
  89   9 * 8, 8 * 8,                 /* %esi, %edi */
  90   17 * 8, 19 * 8,               /* %eip, %eflags */
  91   18 * 8, 21 * 8,               /* %cs, %ss */
  92   -1, -1, -1, -1                /* %ds, %es, %fs, %gs */
  93 };
  94 \f
  95
  96 /* Support for debugging kernel virtual memory images.  */
  97
  98 #include <sys/types.h>
  99 #include <machine/pcb.h>
 100 #include <osreldate.h>
 101
 102 #include "bsd-kvm.h"
 103
 104 static int
 105 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 106 {
 107   /* The following is true for FreeBSD 5.2:
 108
 109      The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
 110      %ds, %es, %fs and %gs.  This accounts for all callee-saved
 111      registers specified by the psABI and then some.  Here %esp
 112      contains the stack pointer at the point just after the call to
 113      cpu_switch().  From this information we reconstruct the register
 114      state as it would like when we just returned from cpu_switch().  */
 115
 116   /* The stack pointer shouldn't be zero.  */
 117   if (pcb->pcb_rsp == 0)
 118     return 0;
 119
 120   pcb->pcb_rsp += 8;
 121   regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &pcb->pcb_rip);
 122   regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &pcb->pcb_rbx);
 123   regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);
 124   regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);
 125   regcache_raw_supply (regcache, 12, &pcb->pcb_r12);
 126   regcache_raw_supply (regcache, 13, &pcb->pcb_r13);
 127   regcache_raw_supply (regcache, 14, &pcb->pcb_r14);
 128   regcache_raw_supply (regcache, 15, &pcb->pcb_r15);
 129 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
 130   /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
 131      up until __FreeBSD_version 800074: The removal of these fields
 132      occurred on 2009-04-01 while the __FreeBSD_version number was
 133      bumped to 800075 on 2009-04-06.  So 800075 is the closest version
 134      number where we should not try to access these fields.  */
 135   regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds);
 136   regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es);
 137   regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs);
 138   regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs);
 139 #endif
 140
 141   return 1;
 142 }
 143 \f
 144
 145 /* Provide a prototype to silence -Wmissing-prototypes.  */
 146 void _initialize_amd64fbsd_nat (void);
 147
 148 void
 149 _initialize_amd64fbsd_nat (void)
 150 {
 151   struct target_ops *t;
 152   int offset;
 153
 154   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
 155   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 156
 157   /* Add some extra features to the common *BSD/i386 target.  */
 158   t = amd64bsd_target ();
 159
 160 #ifdef HAVE_PT_GETDBREGS
 161
 162   i386_use_watchpoints (t);
 163
 164   i386_dr_low.set_control = amd64bsd_dr_set_control;
 165   i386_dr_low.set_addr = amd64bsd_dr_set_addr;
 166   i386_dr_low.get_addr = amd64bsd_dr_get_addr;
 167   i386_dr_low.get_status = amd64bsd_dr_get_status;
 168   i386_dr_low.get_control = amd64bsd_dr_get_control;
 169   i386_set_debug_register_length (8);
 170
 171 #endif /* HAVE_PT_GETDBREGS */
 172
 173   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
 174   t->to_find_memory_regions = fbsd_find_memory_regions;
 175   t->to_make_corefile_notes = fbsd_make_corefile_notes;
 176   add_target (t);
 177
 178   /* Support debugging kernel virtual memory images.  */
 179   bsd_kvm_add_target (amd64fbsd_supply_pcb);
 180
 181   /* To support the recognition of signal handlers, i386bsd-tdep.c
 182      hardcodes some constants.  Inclusion of this file means that we
 183      are compiling a native debugger, which means that we can use the
 184      system header files and sysctl(3) to get at the relevant
 185      information.  */
 186
 187 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset
 188
 189   /* We only check the program counter, stack pointer and frame
 190      pointer since these members of `struct sigcontext' are essential
 191      for providing backtraces.  */
 192
 193 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
 194 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
 195 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
 196
 197   /* Override the default value for the offset of the program counter
 198      in the sigcontext structure.  */
 199   offset = offsetof (struct sigcontext, sc_rip);
 200
 201   if (SC_RIP_OFFSET != offset)
 202     {
 203       warning (_("\
 204 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
 205 Please report this to <bug-gdb@gnu.org>."),
 206                offset, SC_RIP_OFFSET);
 207     }
 208
 209   SC_RIP_OFFSET = offset;
 210
 211   /* Likewise for the stack pointer.  */
 212   offset = offsetof (struct sigcontext, sc_rsp);
 213
 214   if (SC_RSP_OFFSET != offset)
 215     {
 216       warning (_("\
 217 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
 218 Please report this to <bug-gdb@gnu.org>."),
 219                offset, SC_RSP_OFFSET);
 220     }
 221
 222   SC_RSP_OFFSET = offset;
 223
 224   /* And the frame pointer.  */
 225   offset = offsetof (struct sigcontext, sc_rbp);
 226
 227   if (SC_RBP_OFFSET != offset)
 228     {
 229       warning (_("\
 230 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
 231 Please report this to <bug-gdb@gnu.org>."),
 232                offset, SC_RBP_OFFSET);
 233     }
 234
 235   SC_RBP_OFFSET = offset;
 236
 237   /* FreeBSD provides a kern.ps_strings sysctl that we can use to
 238      locate the sigtramp.  That way we can still recognize a sigtramp
 239      if its location is changed in a new kernel.  Of course this is
 240      still based on the assumption that the sigtramp is placed
 241      directly under the location where the program arguments and
 242      environment can be found.  */
 243   {
 244     int mib[2];
 245     long ps_strings;
 246     size_t len;
 247
 248     mib[0] = CTL_KERN;
 249     mib[1] = KERN_PS_STRINGS;
 250     len = sizeof (ps_strings);
 251     if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
 252       {
 253         amd64fbsd_sigtramp_start_addr = ps_strings - 32;
 254         amd64fbsd_sigtramp_end_addr = ps_strings;
 255       }
 256   }
 257 }